Challenge of invasive pests

More than 33,000 square miles of California are under quarantine because invasive pest species have been detected that not only threaten the state’s No. 1 industry, agriculture, but also the urban landscape.

The quarantine area is likely to grow as increasingly more invasive species are detected in California, according to Bob Wynn, California Department of Food and Agriculture (CDFA), coordinator for the statewide Pierce’s Disease Control Program.

Wynn directs the 10-year-old program to control the Glassy-Winged Sharpshooter (GWSS), the vector for Pierce’s disease. It has been challenging, but successful in controlling the spread of the deadly grapevine disease.

Wynn detailed the overall CDFA effort in keeping all unwanted pests at bay and he said there are other invasive pest species far more challenging to control and eradicate than GWSS. The number of dangerous pests alone is daunting.

Just a few years ago, Wynn told the annual California Association of Pest Control Advisers (CAPCA) that it would have taken only about 10 minutes to detail invasive species control efforts. This year he took 30 minutes at CAPCA’s annual gathering in Reno, Nev., and still did not cover all the invasive pest species CDFA is trying to control and/or eradicate.

There are more than 20 now identified in the state; nine just in the last year. It is getting so challenging that CDFA has resorting to evaluating risks before spending dwindling state funds to attack an invasive species. The ongong state budget crisis continues to financially handcuff CDFA’s efforts, and the department is considering assessing individual segments of agriculture ag segments fees for the cost of controlling at least some of the invasive species.

Invasive pests are coming so fast, Wynn did not have time to list one of the newest in his pest pictorial catalog that he showed at a CAPCA general session. It is a new drosophila fruit fly species called the spotted winged drosophila (SWD) (drosophila suzukii). It was identified last spring. Drosophila fruit flies have been around forever, but they normally attack rotting fruit. SWD attacks fruit ripening and near harvest on the trees. It devastated many cherry orchards last spring.

Wynn told the 1,200 people at the CAPCA conference that CDFA has good success in controlling the two or three invasive, different fruit flies trapped every year in the state with male annihilation through pesticide laced traps. However, the SWD is already long past the control stage. It has already been identified in many areas of California, Oregon, Washington and Colorado, since it was identified just a few months ago in California.

He told the pest control advisers (PCAs) that they will be faced with SWD in the future. “It is long past the eradication stage,” he noted.

Perhaps the biggest challenge facing CDFA and the state’s $1.6 billion citrus industry is the Asian citrus psyllid (ACP). It has been detected in several Southern California areas and recently in Arizona. It vectors citrus greening, a bacterial disease that has killed 200,000 acres of citrus in Florida. Trees continue to die daily there, according to Wynn. It also threatens 1.2 million acres of Mexican citrus. It’s also in Cuba.

It has never been eradicated anywhere the world. Wynn says CDFA and other agencies are trying to suppress the psyllid while researchers work on how to eradicate it.

One of the challenges is that there is no pheromone for trapping ACP. “Researchers are working on it very hard, but it should have been worked on 20 years ago,” he said.

Wynn said the department is hoping techniques used to control GWSS/Pierce’s disease can be employed to keep ACP from devastating the state’s citrus, once a pheromone is developed.

What makes ACP so insidious is that the citrus greening disease does not show up and kill citrus trees for two to five years after the psyllid has infected the tree with its bacteria. So far, no trees in California and Arizona have been diagnosed with the actual disease, but experts say it is only a matter of time until trees die from citrus greening.

Another troublesome pest has been the light brown apple moth (LBAM). However, it is not because it is necessarily difficult to control and eradicate, but due to protests from Bay Area residents who have filed at least two lawsuits stopping the mating disruption pheromone treatments.

It has forced CDFA to file an Environmental Impact Report. Wynn said that is due in January. In the meantime, the pest continues to spread out of the Bay Area into 16 counties, including Los Angeles.

Opponents are trying to “delist” LBAM as an invasive pest species in California. Wynn said that would be the “worst thing that could happen.” Even if it is delisted in California, the quarantine against any plant or ag commodities moving out of where LBAM has been detected would not be dropped.

Wynn says 48 other states regulate LBAM as an invasive pest, and all would prohibit plant material from the California LBAM quarantine areas moving into those 48 states.

One of the challenges in educating people about the LBAM control effort is the spreading of misinformation via the social media like Facebook and Twitter. “The department is new coming to the table using the social media, but we are now using it,” to provide information, said Wynn.

While residents are protesting LBAM control efforts, it has been new California residents who have provided support for CDFA’s efforts to eradicate the known population of gypsy moth in the state in the Ojai area of Ventura County.

In the northeast U.S, the gypsy moth has defoliated massive forest areas. Ojai residents who once lived there are vocally supporting CDFA in its efforts, stemming any widespread protests.

This Ojai infestation has been treated with Bacillus thuringiensis (B.t.) insecticide, but Wynn said the gypsy moth must go through two lifecycles before the department can determine if the control efforts worked. It will be next year before the department knows if it has been successful.

It is a constant battle to keep invasive insect species out of California, whether they arrive from overseas or the U.S. Wynn said the ports of Los Angeles, Long Beach and Oakland are the first, second and fourth busiest ports in the U.S.

In the Long Beach/Los Angeles ports, Wynn said gypsy moth have been found on 18 ships so far. These ships were kept offshore until the gypsy moths on board were eradicated.

Air travel and cargo ships moving into the state continue to increase. CDFA and the U.S. Department of Agriculture continually monitor that traffic, but are faced with furloughs in the future due to budget cuts. This could hamper detection efforts.

The state currently has 14,000 Japanese beetle traps deployed around the state, mostly around airports. They have intercepted 65 Japanese beetles this year alone. It damages more than 300 different ornamental and agricultural plants.

Fortunately, CDFA has been granted the funds to keep state line border stations open. Fifty percent of invasive pests found in California come from the U.S.

“Border stations are critical to keeping out invasive pests,” emphasized Wynn.

County ag commissioners are using trained dogs to detect invasive pests at parcel delivery companies like FedEx and UPS. Unfortunately, the department has not been able to work out a similar arrangement with the U.S. Postal Service.

“The workload on invasive pests is increasing, but the resources are decreasing,” said Wynn. The $15 billion state debt looms over the department’s budget. This is why CDFA is considering levying fees to industries affected by the invasive species. Public funds are limited.” They are so scarce he said the department now prioritizes the growing list of pests based on risk. Some of these pests are being left off CDFA control efforts.

Pest control advisers (PCAs) are the first line of detection in sighting new invasive species, he notes. “Even though there are repercussions when an invasive pest is found, if we can detect and identify it early (with the help of PCAs), there is a good chance for eradication.”

PCAs and farmers can be apprehensive about reporting suspected new invasive pest species since these usually trigger quarantines and government intervention to prevent their spread.

“It is never good news when a new pest is found, but we ask that PCAs help us help ourselves” to prevent the unnecessary spread of a damaging pest.

email: [email protected]

TAGS: Management
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.